A rare case of annular pustular psoriasis associated with pemphigus foliaceus

Interaction of Psoriasis and Bullous Diseases

Patients with psoriasis are frequently complicated with autoimmune bullous diseases, especially, pemphigoid diseases. It has been known that one-third cases of anti-laminin gamma1 pemphigoid, formerly anti-p200 pemphigoid, are associated with psoriasis whereas bullous pemphigoid is the most frequently associated bullous disease in psoriasis cases regardless of the lack of detectable levels of the accompanying anti-laminin gamma1 autoantibodies. Despite several suggestions, however, the definitive reason of the striking association of psoriasis and these autoimmune bullous diseases remains elusive. In this review, we look over the epidemiological evidence of the association of psoriasis and autoimmune bullous diseases and the information of genetic susceptibilities of each disease, and discuss the possible mechanisms of their complication with reference to the recent understandings of each pathogenesis.

Pemphigus foliaceus with pustular presentation in a patient with psoriasis

Pemphigus foliaceus is a chronic autoimmune disease of the skin, clinically characterized by scaly and crusty cutaneous erosions involving the seborrheic areas. The patient can eventually become erythrodermic. There are reports of atypical cases of pemphigus foliaceus with pustules and neutrophils, and clinical differentiation from generalized pustular psoriasis of von Zumbusch is difficult. We report the case of a 55-year-old man with a history of psoriasis vulgaris that has developed pemphigus foliaceus with pustules, triggered by withdrawal of systemic corticosteroids. This is the first report associating this atypical form of pemphigus with psoriasis, suggesting that an overlap with generalized pustular psoriasis can occur.